1. Field of the Invention
The present invention relates to a composition of a diagnostic biomarker for stomach cancer and a method of diagnosing stomach cancer using the composition.
2. Description of the Related Art
Stomach cancer, which is one of the most prevalent diseases in South Korea and Japan, is the second most common disease to Koreans. Examples of risk factors of stomach cancer are family history, Helicobacter pylori infection, smoking, salty food, processed proteins, spoiled food, or the like, and they are mainly diagnosed through a gastrointestinal series. Regular gastroscopy may be performed to determine the seriousness of stomach cancer, but early detection thereof is difficult. Therefore, by discovering diagnostic markers that are clinically highly specific and sensitive and by using monoclonal antibodies to detect the diagnostic markers, a development of a kit that predicts early diagnosis of stomach cancer and progression of the disease may be promoted.
When measuring peptide markers in blood, there are interfering signals caused by several types of proteins (albumin, immunoglobulin, etc) that are present abundantly within the blood; therefore, when extracting the peptide markers from the blood, a molecular cut-off filter is used to increase a recovery rate.
In general, neurotensin and cholecystokinin are peptides involved in digestion; however, they are also involved in appetite control operating in the brain so that many studies focusing mainly on the operation and function of the brain are in progress so far. After the results of neuropeptide from a mouse brain tissue measured by an enzyme-linked immunosorbent assay (ELISA) were reported, it was then reported that the concentration of neurotensin in a blood sample from a patient with Parkinson's disease increased. Procholecystokinin was proposed as a diagnostic marker of a patient with human Ewing sarcoma. In addition, it was reported that neurotensin and cholecystokinin have been detected with high concentration to obese women in particular. However, with regard to stomach cancer, there is no report yet that neurotensin and cholecystokinin have been utilized as biomarkers.
Based on these reports, the inventors of the present invention measured the concentration of neurotensin and cholecystokinin, respectively, in a blood sample of a patient with stomach cancer and compared and analyzed the measurement with a blood sample of a normal patient. Thus, the inventors established neurotensin and cholecystokinin as diagnostic biomarkers for stomach cancer and also a method of diagnosing stomach cancer using the biomarkers.